If A, Band C be the angles ofa triangle, then of the followingthe incorrectrelationis :

A

$$sin \frac{A+B}{2}=cos \frac{C}{2}$$

B

$$cos \frac{A+B}{2}=sin \frac{C}{2}$$

C

$$tan \frac{A+B}{2}=sec \frac{C}{2}$$

D

$$cot \frac{A+B}{2}=tan \frac{C}{2}$$